Continuing scientific progress in Parkinson's disease (PD) and other parkinsonian syndromes relies upon accurate diagnosis of these disorders and the availability of patients and controls for study. The Ascertainment and Clinical Core of the Duke Udall Parkinson's Disease Research Center of Excellence ("Duke Udall PDRCE") builds on the diagnostic and family ascertainment expertise of the Duke Center for Human Genetics. While the main goal of the core is to provide diagnostic expertise and facilitate the genetic family studies and other multidisciplinary efforts of Duke Udall PDRCE projects, the clinical data, DNA samples and tissue bank resources developed by the core will benefit other independently funded investigations of PD as well. There are three specific aims of the Ascertainment and Clinical Core: 1. Enroll 200 families in genetic studies of PD. 2. Maintain an active autopsy and tissue donation program. 3. Collect and database detailed clinical, family history, and environmental risk factor data on all participants.